When making a search for a song title, a facility name, or the like, a user does not always remember its exact name, and thus in some cases, the user makes the search using a popular name, an abbreviated name, a vaguely and improperly remembered name or the like as a search key. Meanwhile, with respect to a terminal and a device such as a car navigation apparatus and a smartphone not provided with a keyboard as an input device, there may also be a case where the search is made using as the search key a result from voice recognition of a voice signal through a microphone, a result from character recognition of an input through a touch panel, or the like. In either case, a technique is required to make a fuzzy (ambiguous) search for not only a proper name, but also its analogous name in pronunciation or character-string.
An example of a conventional search technique that enables the fuzzy search as mentioned above is proposed in Patent Document 1. An invention according to Patent Document 1 is a search device that makes a fuzzy search using a partial character-string in a search term; when a rating thereof is raised as the partial character-string in the search term is contained at a higher rate in a search target character-string, and as the partial character-string is positioned more forward in the search target character-string, an appropriate search result matching a user's sense can be obtained in a facility name search. This uses the following characteristics: generally, when a name is provided in Japanese to a facility and so on, words and phrases to be highlighted tend to be determined to be positioned forward in the name; and usually, the user tends to feel a higher correlativity between the search target character-string and the search term when the search term is positioned forward in the search target character-string rather than when positioned rearward therein.
For example, when a facility name of “ABCD LAND” is inputted as the search term, the search device searches for a search target character-string including “AB”, “BC”, “CD”, “DL”, “LA”, “AN” and/or “ND” that are its partial character-strings. If two search target character-strings of “ABCD LAND” and “∘x BANK ABCD LAND BRANCH” are obtained as this search result, a higher rating is given to “ABCD LAND” which the user is highly likely to desire.
On the other hand, when a search is made for a song title, a facility name and so on, in many cases, a plurality of correlated key words are used as the search key. For example, when the search is made with such a form of “<artist name><song title>” or “<municipal name><facility name>”, the search result is further narrowed than when the search is made merely with the song title or facility name, so that acquisition of more appropriate search results can be expected.
An example of a conventional searching technique taking into consideration a relationship between such correlated key words is proposed in Patent Document 2. An invention according to Patent Document 2 is a search device in which facility names and their attendant information are previously associated with each other, and an index for every attendant information is formed, so that a search result is obtained by specifying the attendant information from words and phrases in a search query, followed by browsing the index based on the specified attendant information.
For example, when a search query of “PORK BONE, THIN NOODLE” is inputted, the search device specifies that “PORK BONE” is a key word belonging to the attendant information “TASTE”, and then searches for index data of taste previously prepared to thereby acquire the corresponding facility name. Further, the search device specifies that “THIN NOODLE” is a key word belonging to the attendant information “NOODLE”, and then searches for index data of noodle previously prepared to thereby acquire the corresponding facility name. Then, the search device combines these searched results and presents a list of the corresponding facility names to the user as the search results.